Definition - What does Infected File mean?
Techopedia explains Infected File
Other kinds of infections involve deceptive duplication of files and other unusual code alterations. Anti-virus scanners and programs must be constantly updated to catch the many different kinds of viral file infections that are regularly created by hackers. Although infected files can often be contained and repaired or deleted, some are hard to contain, since internal code acts quickly and can have a devastating effect on an operating system.